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createMediator()

createMediator<Events>(): Mediator<Events>

Creates a typed mediator for decoupled component communication.

Components emit events without knowing who handles them. The mediator routes events to registered handlers, enabling loose coupling.

Type Parameters​

Events: Events extends Record<string, unknown>​

Record mapping event names to payload types

Returns: Mediator<Events>​

A mediator with on, emit, and clear methods

Since​

2.4.0

Example​

type UIEvents = {
  buttonClicked: { buttonId: string };
  formSubmitted: { data: FormData };
  modalClosed: { modalId: string };
};

const ui = createMediator`<UIEvents>`();

// Dialog component
ui.on("buttonClicked", ({ buttonId }) => {
  if (buttonId === "confirm") ui.emit("modalClosed", { modalId: "dialog" });
});

// Form component
ui.on("formSubmitted", ({ data }) => {
  validate(data);
  ui.emit("buttonClicked", { buttonId: "confirm" });
});

Handler()<T>​

Type

Handler<T> = (payload) => void

Event handler function type. Replaces the GoF Colleague callback interface.

Type Parameters​

T: T​

The event payload type

Parameters​

payload: T​

Returns: void​

Since​

2.4.0

Mediator<Events>​

Type

Mediator<Events> = object

Mediator interface for typed event routing. Replaces the GoF Mediator abstract class.

Since​

2.4.0

Type Parameters​

Events: Events extends Record<string, unknown>​

Record mapping event names to payload types

Properties​

on(): <K>(event, handler) => () => void​

Register a handler for an event type. Returns unsubscribe function.

Type Parameters​

K: K extends keyof Events​

event: K
handler: Handler<Events[K]>
Returns: > (): void

Returns: void​

emit(): <K>(event, payload) => void​

Emit an event to all registered handlers.

Type Parameters​

K: K extends keyof Events​

event: K
payload: Events[K]
Returns: void

clear(): (event?) => void​

Remove all handlers for an event type, or all handlers if no event specified.

event?: keyof Events
Returns: void